.nes_btn_box {
    max-width: 170px;
    max-height: 180px;
    margin: 0 auto;
    width:100%;
    height:100%;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
    align-content: space-around;
    -webkit-tap-highlight-color: transparent;
}

.nes_btn_box .btn {
    height:30px;
    line-height: 30px;
    text-align: center;
    background-color: lightcoral;
    color: lightcyan;
    cursor: pointer;
    border-radius: 5px;
    opacity: 0.5;
}
/* 点击时按钮的背景色 */
.nes_btn_box .btn.isTouch {
    background-color: linen;
}

.nes_btn_box .btn-select,
.nes_btn_box .btn-start {
    width:40%;
}
.nes_btn_box .btn-ab {
    width:80%;
    height:60px;
    line-height: 60px;
}

.nes_btn_box .btn-a,
.nes_btn_box .btn-b {
    width:46%;
    height:60px;
    line-height: 60px;
}